A fuel injection system described in published German patent document DE 101 23 867 includes an auxiliary intake which is connected via a line to an interior chamber of the fuel injector. A purifying agent or a mixture from fuel and purifying agent(s) is able to be conveyed to the spray-discharge orifices of the fuel injector via the auxiliary intake. The purifying agent may be used to rinse the fuel injector and the spray-discharge orifices in order to reduce deposits.
Disadvantageous in the system described in the aforementioned German patent document is, in particular, that each fuel injector of an internal combustion engine must be provided with a corresponding intake, which furthermore must be positioned in a decentralized fashion from the fuel intake of the fuel injectors. The manufacturing expense is thus very high. Furthermore, a second intake, which interconnects the auxiliary intakes, must be installed, which entails further expense in components and installation time.